Boom Box Lunch & Learn: Vehicle Recording

Written by Jacob Cook

At Boom Box Post we host monthly meetings that are followed by an educational lesson we call a “Lunch & Learn.” Topics include a wide variety of sound related skills from noise reduction to synthesis. One of our upcoming TV series features a number of unique race cars and hot rods, so we decided to step out of our comfort zone and into the fascinating world of multi-track vehicle recording. I partnered up with BBP sound effects editor Brad Meyer to take on this monumental task.

Our goal was not only to learn about vehicle recording, but provide an introductory lesson to the other editors in the studio. This way, they would have some basic knowledge to serve as a starting point if they should need to record vehicles in the future. We started by doing A LOT of research.

There are a few recordists who specialize in this type of recording and for our experiment we did as much reading as we could; articles, tutorials and interviews with various recordists all provided an excellent basis of knowledge. Max Lachmann, Charles Deenan, Rob Nokes, the Tonebenders podcast, among many others have posted excellent material on this topic.

We discovered that there were a few ideas that many recordists had in common, both basic principles and more detailed guidance on specific things like mic placement. All recommended recording both onboard microphones, mounted to different parts of the vehicle, simultaneously with exterior mics manned by a recordist. We decided to start with Max Lachmann’s minimum setup according to his article for Asoundeffect.com: “stereo rig for exteriors, and four channels to go onboard to cover exhaust, engine and stereo interior.”

We assessed the tools we had available, and settled on running a Sound Devices 744T with 442 mixer for the onboards and a Tascam HD-P2 for the stereo exterior. For our onboards we chose the Rode NT-4 for the interior, the Sennheiser MKH 8040 for exhaust and an Oktavamod MJE-384K for the engine compartment. For exteriors we used a pair of Sennheiser MKH 416s mounted in blimps to be handheld by our recordists.

Fortunately, we scheduled time for a test record before the lesson day, an enlightening experience. Our takeaways from this test informed our final mic positions and choices. We learned to try positioning the engine compartment mic near the air intake, how to route cables through the trunk and window of the vehicle, and how to potentially draft our exhaust mic to keep it protected from wind.

Following the test, we designed a basic route beginning in our parking lot and running around a few blocks, down a side street where our driver could pick up some speed, and back into our studio lot. By repeating this maneuver we hoped to capture a variety of material including startups, pull-aways, pull-ups, pass-bys, accelerations, decelerations and shut-offs.

To keep our editors involved and learning we rotated the shotgun mics through the team having them first record exterior start-ups and aways as the vehicle pulled out of the lot, then rushing around the corner to the side street to capture pass-bys, which was my favorite part of the lesson.

In our research we learned about 3 kinds of pass-bys. First is stationary, in which a shotgun mic is aimed perpendicular to the road as the vehicle passes by, giving a very short window of time where the vehicle is on-axis to the mic. Next was tracking, where the recordist follows the vehicle with the mic, tracking it as it pulls up and passes by the recording position. Last is my favorite, the whip by, in which the recordist whips the microphone in the opposite direction of the vehicle, like a reverse tracking by, to get a much stronger sense of speed than the other two techniques. We learned that tracking was the most versatile for sfx editorial, while the whip could sound most exciting.

We had our driver Evan follow the route three times to give us a variety of material and give everyone the opportunity to record, and then called it a day.

Seeing as the goal of the session was to learn and teach, it was a huge success. Here are some of the lessons we learned:

Engines get super hot, make sure mics are protected and secured(our gaff tape was melting, zip ties for the win!)

Rear windows can get super hot, make sure mics are secure(again, our gaff tape was melting!)

Drafting mics behind parts of the car can save a lot of trouble when it comes to wind protection

Avoid fan noise in the engine compartment, the air intake can be a great starting point for a distinct sound

Don’t whip your blimp too hard during whip-bys or risk dislodging your mic from its suspension and potentially ruining a take

Look for vehicles with modified exhaust(the Mustang we recorded sounded nice, but lacked a strong character and tone from the exhaust)

Learning about vehicle recording was a hoot! The fascinating combination of technical and creative decision making that attracts many of us to sound editing and design is very present in the highly specialized slice of sound effects recording. We can’t wait to get back out into the field to record some more cars(we’ve got our eyes out for hot rods this time).

Tell us about your favorite sound learning experience in the comments below!